The alignment will be inevitable in your case, but I would be more worried about the damage to the crossmember than just the alignment issue. If the damage is as severe as you claim, a crossmember failure at highway speeds could be catastrophic! Needless to say, the crossmember damage may render an alignment useless.
Do search the threads for tips on proper car jacking to prevent mishaps like that in the future! I'm glad you weren't under the car when it slipped!